Crack detection chip and crack detection method using the same

ABSTRACT

A crack detection chip includes a chip which includes an internal region and an external region surrounding the internal region, a guard ring formed inside the chip along an edge of the chip to define the internal region and the external region, an edge wiring disposed along an edge of the internal region in the form of a closed curve and a pad which is exposed on a surface of the chip and is connected to the edge wiring. The edge wiring is connected to a Time Domain Reflectometry (TDR) module which applies an incident wave to the edge wiring through the pad, and detects a reflected wave formed in the edge wiring to detect a position of a crack.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. § 119 to Korean PatentApplication No. 10-2018-0023638, filed on Feb. 27, 2018 in the KoreanIntellectual Property Office, the disclosure of which is incorporated byreference herein in its entirety.

TECHNICAL FIELD

Exemplary embodiments of the inventive concept relate to a crackdetection chip and a crack detection method using the same.

DISCUSSION OF RELATED ART

When dicing is performed on individual chips in a wafer during anassembling process of a semiconductor chip and a semiconductor package,minute cracks may occur on edges of the chips. Such cracks progress overtime and may cause problems of quality and reliability of thesemiconductor chip and the semiconductor package.

A circuit such as a chipping detect circuit (CDC) may be configured todetect cracks, and if a signal does not return within a certain time, itis determined that a defect occurs in an edge region of a chip. In sucha method, it is possible to know only the presence or absence of cracks,e.g., the occurrence of defects, and it is not possible to accuratelycheck an occurrence position of cracks.

SUMMARY

According to an exemplary embodiment of the inventive concept, a crackdetection chip includes a chip which includes an internal region and anexternal region surrounding the internal region, a guard ring formedinside the chip along an edge of the chip to define the internal regionand the external region, an edge wiring disposed along an edge of theinternal region in the form of a closed curve, and a pad which isexposed on a surface of the chip and is connected to the edge wiring.The edge wiring is connected to a Time Domain Reflectometry (TDR) modulewhich applies an incident wave to the edge wiring through the pad, anddetects a reflected wave formed in the edge wiring to detect a positionof a crack.

According to an exemplary embodiment of the inventive concept, a crackdetection chip includes a substrate including first and second regions,a guard ring which separates the first and second regions, an edgewiring formed so as to be buried in the second region, and a pad whichis connected to the edge wiring and is exposed to an upper surface ofthe substrate. The edge wiring is connected to a Time DomainReflectometry (TDR) module through the pad. The TDR module applies anincident wave to the edge wiring, and detects a reflected wave formed inthe edge wiring to detect a position of a crack.

According to an exemplary embodiment of the inventive concept, a crackdetection chip includes an edge wiring arranged along an edge of a chipand formed in a closed curve shape, and a pad which is exposed to asurface of the chip and is connected to the edge wiring. The edge wiringis connected to a Time Domain Reflectometry (TDR) module which appliesan incident wave to the edge wiring through the pad, and detects areflected wave formed in the edge wiring to detect a position of acrack.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects and features of the inventive concept willbecome more apparent by describing in detail exemplary embodimentsthereof with reference to the attached drawings.

FIG. 1 is a layout diagram for explaining a crack detection chipaccording to an exemplary embodiment of the inventive concept.

FIG. 2 is a cross-sectional view taken along line A-A′ of FIG. 1according to an exemplary embodiment of the inventive concept.

FIG. 3 is a conceptual layout diagram for explaining a connectionbetween the crack detection chip of FIG. 1 and a Time DomainReflectometry (TDR) module according to an exemplary embodiment of theinventive concept.

FIG. 4 is a conceptual diagram for explaining the operation of the crackdetection chip and the TDR module of FIG. 3 according to an exemplaryembodiment of the inventive concept.

FIG. 5 is a graph for explaining a reflected wave distance according tothe detection of a reflected wave over time according to an exemplaryembodiment of the inventive concept.

FIG. 6 is a conceptual diagram for explaining the operation of a crackdetection chip and a TDR module according to an exemplary embodiment ofthe inventive concept.

FIG. 7 is a layout diagram for explaining a crack detection chipaccording to an exemplary embodiment of the inventive concept.

FIG. 8 is a layout diagram for explaining a crack detection chipaccording to an exemplary embodiment of the inventive concept.

FIG. 9 is a block diagram illustrating a positional relation between thecrack detection chip, an emission scope, and a detection unit of FIG. 8according to an exemplary embodiment of the inventive concept.

FIG. 10 is a layout diagram for explaining a crack detection chipaccording to an exemplary embodiment of the inventive concept.

FIG. 11 is a layout diagram for explaining a crack detection chipaccording to an exemplary embodiment of the inventive concept.

FIG. 12 is a layout diagram for explaining a crack detection chipaccording to an exemplary embodiment of the inventive concept.

FIG. 13 is a layout diagram for explaining a crack detection chipaccording to an exemplary embodiment of the inventive concept.

FIG. 14 is a conceptual diagram for explaining the operation of thecrack detection chip and a time propagation delay (tPD) unit of FIG. 13according to an exemplary embodiment of the inventive concept.

FIG. 15 is a layout diagram for explaining a crack detection chipaccording to an exemplary embodiment of the inventive concept.

FIG. 16 is a layout diagram for explaining a crack detection chipaccording to an exemplary embodiment of the inventive concept.

FIG. 17 is a layout diagram for explaining a crack detection chipaccording to an exemplary embodiment of the inventive concept.

FIG. 18 is a flowchart for explaining a crack detection method accordingto an exemplary embodiment of the inventive concept.

FIG. 19 is a flowchart for explaining a crack detection method accordingto an exemplary embodiment of the inventive concept.

FIG. 20 is a flowchart for explaining an emission scope crack detectionoperation of FIG. 19 in detail according to an exemplary embodiment ofthe inventive concept.

FIG. 21 is a flowchart for explaining a crack detection method accordingto an exemplary embodiment of the inventive concept.

FIG. 22 is a flowchart for explaining an operation of determining thepresence or absence of a tPD crack of FIG. 21 in detail according to anexemplary embodiment of the inventive concept.

FIG. 23 is a flowchart for explaining a crack detection method accordingto an exemplary embodiment of the inventive concept.

FIG. 24 is a flowchart for explaining a crack detection method accordingto an exemplary embodiment of the inventive concept.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Exemplary embodiments of the inventive concept provide a crack detectionchip capable of accurately grasping the crack position of an edge regionof a chip.

Exemplary embodiments of the inventive concept also provide a crackdetection method capable of accurately grasping the crack position of anedge region of a chip.

Exemplary embodiments of the inventive concept will be described morefully hereinafter with reference to the accompanying drawings. Likereference numerals may refer to like elements throughout thisapplication.

Hereinafter, a crack detection chip according to an exemplary embodimentof the inventive concept will be described with reference to FIGS. 1 to5.

FIG. 1 is a layout diagram for explaining a crack detection chipaccording to an exemplary embodiment of the inventive concept, and FIG.2 is a cross-sectional view taken along line A-A′ of FIG. 1 according toan exemplary embodiment of the inventive concept.

Referring to FIGS. 1 and 2, a crack detection chip according to anexemplary embodiment of the inventive concept includes a chip 10, aguard ring 20, a first edge wiring 100, and a pad 200.

The chip 10 may include constituent elements other than the chip 10. Thechip 10 may be obtained by dicing a substrate to a certain size. Inother words, a plurality of chips 10 may be manufactured by cutting thesubstrate of a wafer level. For example, the chip 10 may be manufacturedby cutting a wafer of a semiconductor material such as silicon.

As illustrated in FIG. 1, a shape of a horizontal plane of the chip 10may be square. The shape of the chip 10 may be defined by four sidesextending in a first direction X or a second direction Y. The firstdirection X and the second direction Y may be perpendicular to eachother. However, the inventive concept is not limited thereto.

An upper surface of the chip 10 may be formed in a third direction Z.The third direction Z may be perpendicular to both the first direction Xand the second direction Y. If the first direction X and the seconddirection Y are a horizontal direction, the third direction Z may be avertical direction.

The chip 10 may include an internal region Ra and an external region Rb.The external region Rb may be an edge region of the chip 10. In otherwords, the external region Rb may be a region formed along the outeredge of the chip 10. For example, the external region Rb may refer to aregion located outside on the basis of the guard ring 20 among theregions of the chip 10.

The internal region Ra may be a region surrounded by the external regionRb. In other words, the external region Rb is located along the edge ofthe internal region Ra, and the external region Rb may surround theinternal region Ra. The configuration in which the external region Rbsurrounds the internal region Ra may be illustrated on a horizontalplane defined by the first direction X and the second direction Y. Inother words, as illustrated in FIG. 1, the external region Rb maysurround the internal region Ra and may be arranged in an annular form.

The internal region Ra and the external region Rb may be defined by theguard ring 20. For example, the internal region Ra may be a regionlocated inside the guard ring 20, and the external region Rb may be aregion located outside the guard ring 20. The region in which the guardring 20 is formed may not belong either to the internal region Ra or theexternal region Rb.

The internal region Ra may be a region in which elements actuallyoperating on the chip 10 are formed. In contrast, the external region Rbmay be a region in which no element is formed or dummy elements areformed. The external region Rb may be a place having a space margin incase of a damaged part when dicing the wafer to the chip 10. In otherwords, the external region Rb may be a scribe line.

Even if a crack, e.g., a cracking phenomenon of the chip 10 occurs inthe external region Rb, there may be no problem in the direct operationof the chip 10. However, when cracks occur in the internal region Ra ofthe chip 10 or progress from the external region Rb to the internalregion Ra, the reliability of the operation of the chip 10 may begreatly impaired. Therefore, for normal operation of the chip 10, cracksshould be prevented from forming in the internal region Ra.

The guard ring 20 may be located between the internal region Ra and theexternal region Rb. The guard ring 20 may serve to block progress of theabove-described cracks from the external region Rb to the internalregion Ra.

Further, the guard ring 20 may perform a moisture absorption actionwhich prevents external moisture from entering the inside of the chip10. In other words, when moisture enters the internal region Ra of thechip 10, the elements located in the internal region Ra of the chip 10may be damaged or malfunction. The guard ring 20 may prevent suchproblems.

The guard ring 20 may be formed while making a closed curve along theedge of the chip 10. Here, “closed curve” refer to ring shapes that arein contact with one another, but does not mean that the extended portionof the guard ring 20 necessarily has curvature. For example, thehorizontal arrangement shape of the guard ring 20 may be a polygon suchas a rectangle, rather than a circle or an ellipse.

For example, the horizontal shape of the guard ring 20 may be arectangle having four sides extending in the first direction X or thesecond direction Y. In other words, the guard ring 20 may be formedinside the chip 10 along the edge of the chip 10 and have a rectangularhorizontal shape similar to the shape of the chip 10. However, theinventive concept is not limited thereto. In other words, as the shapeof the chip 10 changes, the arrangement shape of the guard ring 20 mayalso change.

Alternatively, the shape of the chip 10 and the arrangement shape of theguard ring 20 may be different from each other. In other words, sincethe guard ring 20 is intended to protect the internal region Ra of thechip 10, as long as it is possible to protect the internal region Ra ofthe chip 10, any form or shape of the guard ring 20 may be arranged.

A plurality of guard rings 20 may be provided. When the plurality ofguard rings 20 is provided as compared to the case where the guard ring20 has a single structure, the probability of preventing the progress ofcracks naturally increases, and the possibility of blocking moisturepermeation into the internal region Ra may also increase.

The guard ring 20 may include a first guard ring 21, a second guard ring22, and a third guard ring 23. However, the inventive concept is notlimited thereto. Three guard rings 20 are merely exemplary, and thenumber of guard rings 20 may vary depending on the need and purpose.

The first guard ring 21 may be in direct contact with the externalregion Rb. The outside of the first guard ring 21 may be the externalregion Rb. The second guard ring 22 may be located inside the firstguard ring 21. Likewise, the third guard ring 23 may be located insidethe second guard ring 22. In other words, the third guard ring 23 may bein direct contact with the internal region Ra. The inside of the thirdguard ring 23 may be the internal region Ra.

The first guard ring 21 and the second guard ring 22 may be spaced apartfrom each other by a first distance d1. Similarly, the second guard ring22 and the third guard ring 23 may be spaced apart from each other bythe first distance d1. However, the inventive concept is not limitedthereto.

The guard ring 20 may be formed on the upper surface of the chip 10 tobe deep in the third direction Z. Since the guard ring 20 is formed tomerely prevent cracks of the external region Rb, external moisture, andthe like, the guard ring 20 may be isolated without being connected toother elements. This is substantially the same for each of the pluralityof guard rings 20. In other words, the first guard ring 21, the secondguard ring 22, and the third guard ring 23 may be disposed to be spacedapart from one another without being in contact with one another.

The guard ring 20 may include a metal material. For example, the guardring 20 may include, but is not limited to, at least one of tungsten,copper, cobalt, or aluminum.

The first edge wiring 100 may be located in the internal region Ra. Inother words, the first edge wiring 100 may be formed along the edge ofthe internal region Ra. Therefore, the first edge wiring 100 may belocated inside the guard ring 20. In particular, in FIGS. 1 and 2, thefirst edge wiring 100 may be located inside the third guard ring 23.

The first edge wiring 100 may be separated from the guard ring 20 by asecond distance d2. The second distance d2 may be larger than the firstdistance d1. However, the inventive concept is not limited thereto. Thefirst distance d1 between the plurality of guard rings is effectively asmall space to prevent progress of cracks. In contrast, the seconddistance d2 between the first edge wiring 100 and the guard ring 20 maybe a certain distance or more so as not to be coupled to each other. Asa result, the second distance d2 may be larger than the first distanced1.

Since the first edge wiring 100 is formed along the edge of the internalregion Ra, it may be arranged in a shape corresponding to the shape ofthe internal region Ra. In other words, as illustrated in FIG. 1, thefirst edge wiring 100 may have a rectangular horizontal shape similar tothe shape of the internal region Ra.

The first edge wiring 100 may include a first line 100_1, a second line100_2, a third line 100_3, and a fourth line 100_4. The first line 100_1and the second line 100_2 may extend in the second direction Y and maybe separated from each other in the first direction X. The third line100_3 and the fourth line 100_4 may extend in the first direction X andmay be separated from each other in the second direction Y. The firstline 100_1, the second line 100_2, the third line 100_3 and the fourthline 100_4 may correspond to each side of a rectangle defined by thefirst edge wiring 100.

The first edge wiring 100 may be a buried wiring. In other words, thefirst edge wiring 100 may not be exposed to the outside through theupper surface or the lower surface of the chip 10. In other words, theupper surface of the first edge wiring 100 may not be in contact withthe upper surface of the chip 10, and the lower surface of the firstedge wiring 100 may not be in contact with the lower surface of the chip10.

The width of the first edge wiring 100 in the third direction Z may besmaller than the width of the guard ring 20 in the third direction Z. Inthe case of the guard ring 20, it is necessary to isolate the largest orwidest region of the external region Rb to prevent cracks and moisture.In contrast, since the first edge wiring 100 is merely for detecting thepresence or absence of cracks, the width of the first edge wiring 100 inthe third direction Z may be smaller than the width of the guard ring 20in the third direction Z.

The first edge wiring 100 may be electrically connected to the pad 200.The first edge wiring 100 may be in contact with an internal wiring 110so as to be electrically connected to the pad 200. The internal wiring110 may be a wiring that connects the pad 200 and the first edge wiring100 in the horizontal direction, e.g., the first direction X.

The internal wiring 110 may be connected to the pad 200 through acontact 210. The contact 210 may connect the pad 200 and the internalwiring 110 in the vertical direction, e.g., the third direction Z.

The internal wiring 110, the contact 210, and the first edge wiring 100may include a conductor. For example, the internal wiring 110, thecontact 210, and the first edge wiring 100 may include a metal. Themetal may include, for example, at least one of tungsten, copper,cobalt, or aluminum.

The above-described configuration of the internal wiring 110 and thecontact 210 is merely exemplary. In other words, as long as the firstedge wiring 100 and the pad 200 can be electrically connected to eachother, at least one of the internal wiring 110 and the contact 210 maybe omitted. Alternatively, the first edge wiring 100 and the pad 200 mayalso be electrically connected to each other through elements other thanthe internal wiring 110 and the contact 210.

The pad 200 may be exposed on the upper surface of the chip 10. The pad200 may perform the role of a path through which other external modulescan be connected to the inside of the chip 10. As described above, thepad 200 may be electrically connected to the first edge wiring 100. Thepad 200 may transfer clock signals and input and output signals to otherconstituent elements of the chip 10.

A plurality of pads 200 may be provided. A part of the plurality of pads200 may be connected to the first edge wiring 100, and the other partthereof may be connected to other components.

FIG. 3 is a conceptual layout diagram for explaining a connectionbetween the crack detection chip of FIG. 1 and a Time DomainReflectometry (TDR) module according to an exemplary embodiment of theinventive concept, and FIG. 4 is a conceptual diagram for explaining theoperation of the crack detection chip and the TDR module of FIG. 3according to an exemplary embodiment of the inventive concept. FIG. 5 isa graph for explaining a reflected wave distance according to thedetection of a reflected wave over time according to an exemplaryembodiment of the inventive concept.

Referring to FIGS. 3 to 5, the first edge wiring 100 may be electricallyconnected to a TDR module 300 via the pad 200. The TDR module 300 maydetect a crack CR of the edge region of the chip 10, using time domainreflectometry.

For example, the TDR module 300 may apply an incident wave to the firstedge wiring 100 through the pad 200. When the incident wave encountersthe crack CR while traveling through the first edge wiring 100, theincident wave may form a reflected wave.

In other words, when the first edge wiring 100 is disconnected by thecrack CR, different media such as the first edge wiring 100 and thecrack CR may be in contact with each other. A part of the incident waveis reflected and a part thereof is transmitted at the boundary surfacebetween the two media. As a result, a reflected wave is formed andtravels in a direction opposite to a traveling direction of the incidentwave.

The TDR module 300 may sense the reflected wave traveling in a directionopposite to the incident wave. The TDR module 300 may calculate a firstreflected wave distance L by calculating an application time point ofthe incident wave and an arrival time point of the reflected wave.

The first reflected wave distance L may refer to a distance from theposition at which the crack CR is formed to the TDR module 300 at whichthe reflected wave arrives. The TDR module 300 detects the firstreflected wave distance L and may accurately check the position at whichthe crack CR occurs accordingly. The first reflected wave distance L maybe calculated through the velocity of the incident wave, the velocity ofthe reflected wave, the arrival time, and the like. A point of t=0 ofFIG. 5 may refer to a time point at which the reflected wave isgenerated.

The crack detection chip according to the present exemplary embodimentmay accurately detect at which portion the crack is located, rather thansimply determining whether or not a crack exists in the edge region. Asa result, it is possible to check which part of the chip 10 should besupplemented, and it is possible to track which process in themanufacturing processes of the chip 10 may be a problem. Further, it isalso possible to change the design of the chip 10 later in considerationof the durability of the chip 10.

In other words, the crack detection chip according to the presentexemplary embodiment can not only simply check and supplement thedurability of the current chip 10 accordingly, but also improve thedesign and process elements of the chip 10 to be produced in the future.

Hereinafter, the crack detection chip according to an exemplaryembodiment of the inventive concept will be described with reference toFIG. 6. Repeat descriptions of similar elements will be omitted orsimplified.

FIG. 6 is a conceptual diagram for explaining the operation of a crackdetection chip and a TDR module according to an exemplary embodiment ofthe inventive concept.

Referring to FIG. 6, the TDR module 300 may not recognize the firstreflected wave distance L. In other words, when the limit of the minimumdistance that can be recognized by the TDR module 300 is larger than thesize of the first reflected wave distance L, the TDR module 300 may notimmediately detect the first reflected wave distance L.

In such a case, the TDR module 300 may recognize a second reflected wavedistance L′ instead of the first reflected wave distance L. The secondreflected wave distance L′ may be a distance obtained by adding thelength of the first edge wiring 100 to the first reflected wave distanceL. When the TDR module 300 recognizes the second reflected wave distanceL′, since the second reflected wave distance L′ is larger than thelength of the first edge wiring 100, the difference obtained bysubtracting the length of the first edge wiring 100 from the secondreflected wave distance L′ may be recognized as the reflected wavedistance L. In the crack detection chip according to the presentexemplary embodiment, since the length of the first edge wiring 100 hasan already fixed numerical value, the crack CR can be easily detected inspite of limits of the recognition capability of the TDR module 300.

Unlike FIG. 6, when the limit of the minimum distance that can berecognized by the TDR module 300 is larger than the second reflectedwave distance L′, it is possible to use a reflected wave distance towhich an integer multiplication of the length of the first edge wiring100 is added. Through this, it is possible to accurately detect theposition of the crack CR, regardless of the hardware performance of theTDR module 300.

Hereinafter, a crack detection chip according to an exemplary embodimentof the inventive concept will be described referring to FIG. 7. Repeatdescriptions will be omitted or simplified.

FIG. 7 is a layout diagram for explaining a crack detection chipaccording to an exemplary embodiment of the inventive concept.

Referring to FIG. 7, the crack detection chip according to an exemplaryembodiment of the inventive concept includes a second edge wiring 101.

The second edge wiring 101 may have an uneven shape. The second edgewiring 101 may include a first portion P1 and a second portion P2.

The first portion P1 may be a portion spaced apart from the guard ring20, e.g., the third guard ring 23, by the second distance d2. Incontrast, the second portion P2 may be a portion spaced apart from thethird guard ring 23 by a third distance d3. The third distance d3 may belarger than the second distance d2.

The second edge wiring 101 may include a plurality of first portions P1and a plurality of second portions P2. The second edge wiring 101 may beformed by alternatively extending a plurality of first portions P1 and aplurality of second portions P2. Accordingly, the second edge wiring 101may have an uneven, zigzag shape.

The crack detection chip according to the present exemplary embodimentmay secure a reflected wave path longer than the first edge wiring(e.g., 100 of FIG. 1) of the above-described exemplary embodiment,through the second edge wiring 101 having the uneven shape.

Through this, the TDR module 300 may acquire the reflected wave distancelarger than the limit of the minimum distance that can be more easilyrecognized by the TDR module 300. Therefore, the TDR module 300 caneasily recognize the reflected wave distance, without adding anarithmetic process of adding an integer multiplication of the length ofthe second edge wiring 101, as described above.

A crack detection chip according to an exemplary embodiment of theinventive concept will be described below with reference to FIGS. 8 and9. Repeat descriptions of will be omitted or simplified.

FIG. 8 is a layout diagram for explaining a crack detection chipaccording to an exemplary embodiment of the inventive concept, and FIG.9 is a block diagram illustrating a positional relation between thecrack detection chip, an emission scope, and a detection unit of FIG. 8,according to an exemplary embodiment of the inventive concept.

Referring to FIGS. 8 and 9, in the chip 10 of the crack detection chipaccording to an exemplary embodiment of the inventive concept, a currentinput module 400 is connected to the first edge wiring 100 through thepad 200, and the first edge wiring 100 may be inspected by an emissionscope 1000.

The current input module 400 may apply a heat generation current to thefirst edge wiring 100. If a crack exists in the first edge wiring 100,since the resistance is higher in the portion in which the crack existsthan in other portions having no crack, heat may be generated by theheat generation current.

The emission scope 1000 is located on the chip 10 and may inspect thechip 10 as a whole. The emission scope 1000 may check a portion to beheated, and may detect a portion of the first edge wiring 100 to beheated by the heat generation current. The emission scope 1000 mayacquire information on a heat generation position in the form of animage. In other words, the emission scope 1000 may acquire imageinformation Ia including the heat generation position. The emissionscope 1000 may transmit the image information Ia to a detection unit410.

The detection unit 410 may receive current input information Ib from thecurrent input module 400. The current input information Ib may includeinformation about what magnitude of current is applied to the first edgewiring 100 by the current input module 400, or what magnitude of voltageis applied to the first edge wiring 100. Further, the current inputinformation Ib may include size information of the chip 10 and sizeinformation of the first edge wiring 100. However, the inventive conceptis not limited thereto.

The detection unit 410 may accurately detect which part of the chip 10has a crack through the current input information Ib and the imageinformation Ia.

Hereinafter, a crack detection chip according to an exemplary embodimentof the inventive concept will be described referring to FIG. 10. Repeatdescriptions will be omitted or simplified.

FIG. 10 is a layout diagram for explaining a crack detection chipaccording to an exemplary embodiment of the inventive concept.

Referring to FIG. 10, the crack detection chip according to an exemplaryembodiment of the inventive concept may include a third edge wiring 102.

The third edge wiring 102 may include a first wiring 100 a and a secondwiring 100 b. The first wiring 100 a may be arranged between the secondwiring 100 b and the guard ring 20. The second wiring 100 b may belocated inside the first wiring 100 a.

The first wiring 100 a and the second wiring 100 b may be disposed to bespaced apart from each other. The first wiring 100 a and the secondwiring 100 b may be connected to the current input module 400 throughthe pad 200. The first wiring 100 a and the second wiring 100 b may beconnected to the current input module 400 independently from each otherthrough the different pads 200.

The current input module 400 may apply different currents or voltages tothe first wiring 100 a and the second wiring 100 b. For example, thecurrent input module 400 may apply a VDD voltage to the first wiring 100a and may apply a VSS voltage to the second wiring 100 b. Accordingly,heat generation currents of different magnitudes may be applied to thefirst wiring 100 a and the second wiring 100 b.

If a crack occurs, in a case where a plurality of different levels ofvoltage are applied as compared with a single voltage, the emissionscope 1000 may more clearly check the heat generation position. This isbecause the degree of generation of heat of photons differs depending onthe magnitude of voltage or current.

Therefore, the crack detection chip according to the present exemplaryembodiment may more precisely detect the crack position.

Hereinafter, a crack detection chip according to an exemplary embodimentof the inventive concept will be described referring to FIG. 11. Repeatdescriptions will be omitted or simplified.

FIG. 11 is a layout diagram for explaining a crack detection chipaccording to an exemplary embodiment of the inventive concept.

Referring to FIG. 11, the first edge wiring 100 of the crack detectionchip according to an exemplary embodiment of the inventive concept maybe connected to both the TDR module 300 and the current input module400.

As described above, the TDR module 300 may detect a crack, using timedomain reflectometry. The current input module 400 may detect a crackthrough the emission scope 1000 and the detection unit 410.

A controller 500 may be connected to both the TDR module 300 and thecurrent input module 400. The controller 500 may decide tosimultaneously execute the crack detection methods of the TDR module 300and the current input module 400 or to sequentially execute the crackdetection methods. Alternatively, the controller 500 may perform acontrol to execute only the crack detection method of either the TDRmodule 300 or the current input module 400.

For example, when the result of the crack detection method of the TDRmodule 300 is unclear, the controller 500 may perform the crackdetection method using the current input module 400, the emission scope1000, and the detection unit 410. Conversely, when the result of thecrack detection method using the current input module 400, the emissionscope 1000, and the detection unit 410 is unclear, the controller 500may perform the crack detection method of the TDR module 300. Thecontroller 500 may acquire more accurate crack position by combining thetwo results.

Alternatively, when the reliability of the result of the crack detectionmethod executed first is high, the controller 500 may not performanother crack detection method. As a result, it is possible to minimizethe resources executed for crack detection.

Depending on the type of crack, there may be a difference betweenaccuracy of the method of the TDR module 300 and accuracy of the methodof the emission scope 1000. Therefore, the crack detection chipaccording to the present exemplary embodiment may more accurately andefficiently detect cracks by appropriately using the two methods throughthe controller 500.

Hereinafter, a crack detection chip according to an exemplary embodimentof the inventive concept will be described with reference to FIG. 12.Repeat descriptions will be omitted or simplified.

FIG. 12 is a layout diagram for explaining a crack detection chipaccording to an exemplary embodiment of the inventive concept.

Referring to FIG. 12, the first edge wiring 100 of the crack detectionchip according to an exemplary embodiment of the inventive concept maybe connected to a time propagation delay (tPD) unit 600.

The tPD unit 600 may be connected to the first edge wiring 100 throughthe pad 200. The tPD unit 600 may apply an input signal to the firstedge wiring 100. The input signal applied to the first edge wiring 100by the tPD unit 600 travels along the first edge wiring 100 and mayreturn to the tPD unit 600 again. The tPD unit 600 may determine thepresence or absence of a crack by measuring an arrival time from thetime point when the input signal is applied to the time point when theinput signal returns again.

The tPD unit 600 may determine the presence or absence of a crack bycomparing a new arrival time with a reference arrival time. Thereference arrival time is stored in advance and represents an arrivaltime when no crack exists. If the new arrival time becomes longer thanthe reference arrival time, the tPD unit 600 may determine that a crackexists.

The controller 500 may first instruct the tPD unit 600 to determine thepresence or absence of a crack. Subsequently, when the tPD unit 600determines that a crack exists, the controller 500 may instruct the TDRmodule 300 to detect the correct position of the crack.

The crack detection chip according to the present exemplary embodimentfirst simply determines the presence or absence of cracks by the tPDunit 600, and operates the TDR module 300 only when it is determinedthat there is a crack. Accordingly, efficiency of crack detection can bedramatically enhanced.

Hereinafter, a crack detection chip according to an exemplary embodimentof the inventive concept will be described with reference to FIGS. 13and 14. Repeat descriptions will be omitted or simplified.

FIG. 13 is a layout diagram for explaining the crack detection chipaccording to an exemplary embodiment of the inventive concept, and FIG.14 is a conceptual diagram illustrating the operation of the crackdetection chip and a time propagation delay (tPD) unit of FIG. 13according to an exemplary embodiment of the inventive concept.

Referring to FIGS. 13 and 14, the crack detection chip according to anexemplary embodiment of the inventive concept may include a divided edgewiring 150.

The divided edge wiring 150 may be disposed in an inner direction of thefirst edge wiring 100. However, the inventive concept is not limitedthereto. In exemplary embodiments of the inventive concept, the dividededge wiring 150 may also be located in an outer direction of the firstedge wiring 100.

Like the first edge wiring 100, the divided edge wiring 150 may bedisposed in a closed curve shape along the edge of the chip 10. Thedivided edge wiring 150 may include a first divided edge wiring 150 a, asecond divided edge wiring 150 b, a third divided edge wiring 150 c, anda fourth divided edge wiring 150 d. However, the configuration in whichthe divided edge wiring 150 is divided into four portions is only oneexample, and the divided edge wiring 150 may be variously divided.

The first divided edge wiring 150 a, the second divided edge wiring 150b, the third divided edge wiring 150 c, and the fourth divided edgewiring 150 d may be electrically insulated from one another. Further,the first divided edge wiring 150 a, the second divided edge wiring 150b, the third divided edge wiring 150 c, and the fourth divided edgewiring 150 d may be electrically connected to different pads 200.

The tPD unit 600 may include a first tPD unit 600 a, a second tPD unit600 b, a third tPD unit 600 c, and a fourth tPD unit 600 d. For example,the first tPD unit 600 a may be electrically connected to the firstdivided edge wiring 150 a through the pad 200, and the second tPD unit600 b may be electrically connected to the second divided edge wiring150 b through the pad 200. The third tPD unit 600 c may be electricallyconnected to the third divided edge wiring 150 c through the pad 200,and the fourth tPD unit 600 d may be electrically connected to thefourth divided edge wiring 150 d through the pad 200.

The first tPD unit 600 a, the second tPD unit 600 b, the third tPD unit600 c, and the fourth tPD unit 600 d may apply clock (CLK) signals andreceive an output DQ0. Thus, in the crack detection chip according tothe present exemplary embodiment, the tPD unit 600 and the divided edgewiring 150 may determine the presence or absence of cracks by dividingthe region. Thus, it is possible to more accurately grasp which region acrack is located.

The controller 500 determines which region has a crack through the firsttPD unit 600 a, the second tPD unit 600 b, the third tPD unit 600 c, andthe fourth tPD unit 600 d, and may accurately determine the position ofthe crack through the TDR module 300 and the first edge wiring 100 onthe basis of the result thereof.

Accordingly, the crack detection chip according to the present exemplaryembodiment simply determines the presence or absence of cracks by thefour tPD units 600, and only when it is determined that there is acrack, the TDR module 300 is operated. Accordingly, the efficiency ofcrack detection can be dramatically enhanced. In addition, since it ispossible to first determine the approximate crack position by the fourtPD units 600, it is possible to more accurately determine the positionof the crack.

Hereinafter, a crack detection chip according to an exemplary embodimentof the inventive concept will be described with reference to FIG. 15.Repeat descriptions will be omitted or simplified.

FIG. 15 is a layout diagram for explaining the crack detection chipaccording to an exemplary embodiment of the inventive concept.

Referring to FIG. 15, the first edge wiring 100 of the crack detectionchip according to an exemplary embodiment of the inventive concept maybe connected to both the current input module 400 and the tPD unit 600.

As described above, the current input module 400 may detect cracksthrough the emission scope 1000 and the detection unit 410, and the tPDunit 600 may determine the presence or absence of cracks through theinput signal.

The controller 500 may first instruct the tPD unit 600 to determine thepresence or absence of a crack. Subsequently, when the tPD unit 600determines that the crack exists, the controller 500 instructs thecurrent input module 400, the emission scope 1000, and the detectionunit 410 to detect the correct position of the crack.

The crack detection chip according to the present exemplary embodimentfirst simply determines the presence or absence of cracks by the tPDunit 600, and only when it is determined that there is a crack, thecrack detection chip operates the current input module 400, the emissionscope 1000, and the detection unit 410. Accordingly, the efficiency ofcrack detection can be dramatically enhanced.

Hereinafter, a crack detection chip according to an exemplary embodimentof the inventive concept will be described with reference to FIG. 16.Repeat descriptions will be omitted or simplified.

FIG. 16 is a layout diagram for explaining the crack detection chipaccording to an exemplary embodiment of the inventive concept.

Referring to FIG. 16, the first edge wiring 100 of the crack detectionchip according to an exemplary embodiment of the inventive concept maybe connected to the TDR module 300, the current input module 400, andthe tPD unit 600.

As described above, the TDR module 300 may detect a crack using timedomain reflectometry. The current input module 400 may detect a crackthrough the emission scope 1000 and the detection unit 410. The tPD unit600 may determine the presence or absence of a crack through the inputsignal.

The controller 500 may first instruct the tPD unit 600 to determine thepresence or absence of a crack. Subsequently, if the tPD unit 600determines that a crack exists, the controller 500 may instruct the TDRmodule 300 or the current input module 400, the emission scope 1000, andthe detection unit 410 to detect a correct position of the crack.

The controller 500 may decide to execute simultaneously or sequentiallythe crack detection methods of the TDR module 300 and the current inputmodule 400. Alternatively, the controller 500 may perform the control toexecute only one crack detection method of the TDR module 300 or thecurrent input module 400.

Through this, the crack detection chip according to the presentexemplary embodiment may more accurately, efficiently, and accuratelydetect cracks, by appropriately using the two methods through thecontroller 500.

Hereinafter, a crack detection chip according to an exemplary embodimentof the inventive concept will be described with reference to FIG. 17.Repeat descriptions will be omitted or simplified.

FIG. 17 is a layout diagram for explaining the crack detection chipaccording to an exemplary embodiment of the inventive concept.

Referring to FIG. 17, the crack detection chip according to an exemplaryembodiment of the inventive concept includes the divided edge wiring150, and the first edge wiring 100 may be connected to the TDR module300, the current input module 400, and the four tPD units 600.

The four tPD units 600, e.g., the first tPD unit 600 a, the second tPDunit 600 b, the third tPD unit 600 c, and the fourth tPD unit 600 d, maycorrespond to the first divided edge wiring 150 a, the second dividededge wiring 150 b, the third divided edge wiring 150 c, and the fourthdivided edge wiring 150 d, respectively.

The controller 500 determines in which region a crack exists through thefirst tPD unit 600 a, the second tPD unit 600 b, the third tPD unit 600c, and the fourth tPD unit 600 d, and may accurately determine theposition of the crack on the basis of the result, through the TDR module300, or the current input module 400, the emission scope 1000, and thedetection unit 410.

Thus, the crack detection chip according to the present exemplaryembodiment may first simply determine the presence or absence of crackby the four tPD units 600, and only when it is determined that there isa crack, the crack detection chip operates the TDR module 300 or thecurrent input module 400, the detection unit 410, and the emission scope1000. Accordingly, the efficiency of crack detection can be dramaticallyenhanced. Additionally, since the approximate crack position may bedetermined first by the plurality of tPD units 600, the position of thecrack may be more accurately determined.

Hereinafter, a crack detection method according to an exemplaryembodiment of the inventive concept will be described with reference toFIGS. 3 to 5 and 18. Repeat descriptions will be omitted or simplified.

FIG. 18 is a flowchart for explaining the crack detection methodaccording to an exemplary embodiment of the inventive concept.

Referring to FIG. 18, an incident wave is applied (S110).

For example, referring to FIGS. 3 to 5, the TDR module 300 may apply anincident wave to the first edge wiring 100 through the pad 200. Theincident wave may form a reflected wave when encountering a crack CRwhile traveling through the first edge wiring 100.

Referring again to FIG. 18, a reflected wave is detected (S120).

For example, referring to FIGS. 3 to 5, the TDR module 300 may detectthe reflected wave traveling in a direction opposite to the incidentwave.

Referring again to FIG. 18, the arrival time is calculated (S130).

For example, referring to FIGS. 3 to 5, the TDR module 300 calculatesthe first reflected wave distance L by calculating the application timepoint of the incident wave and the arrival time point of the reflectedwave. The first reflected wave distance L may refer to a distance fromthe position at which the crack CR is formed to the TDR module 300 atwhich the reflected wave arrives. The TDR module 300 detects the firstreflected wave distance L and may accurately check the position at whichthe crack CR occurs accordingly.

Referring again to FIG. 18, the crack position is calculated (S140).

For example, referring to FIGS. 3 to 5, the first reflected wavedistance L may be calculated through the velocity of the incident wave,the velocity of the reflected wave, the arrival time, and the like.

Hereinafter, a crack detection method according to an exemplaryembodiment of the inventive concept will be described with reference toFIGS. 9 to 11, 19, and 20. Repeat descriptions will be omitted orsimplified.

FIG. 19 is a flowchart for explaining the crack detection methodaccording to an exemplary embodiment of the inventive concept, and FIG.20 is a flowchart for explaining an emission scope crack detectingoperation of FIG. 19 in detail according to an exemplary embodiment ofthe inventive concept.

Referring to FIGS. 19 and 20, the crack detection is executed throughthe emission scope 1000 (S50), and a heat generation current is applied(S51).

For example, referring to FIGS. 9 to 11, the current input module 400may apply the heat generation current to the first edge wiring 100. If acrack is present in the first edge wiring 100, since the resistance ishigher in the portion having the crack than in other portions without acrack, heat may be generated by the heat generation current.

Referring again to FIG. 20, inspection is performed with the emissionscope 1000 (S52).

For example, referring to FIGS. 9 to 11, the emission scope 1000 islocated on the chip 10 and may inspect the chip 10 as a whole. Theemission scope 1000 may check a portion to be heated, and may detect aportion of the first edge wiring 100 that generates heat by the heatgeneration current.

Referring again to FIG. 20, a predicted crack generation position isdetected (S53).

For example, referring to FIGS. 9 to 11, the emission scope 1000 mayacquire information on the heat generation position in the form of animage. In other words, the emission scope 1000 may acquire the imageinformation Ia including the heat generation position. The emissionscope 1000 may transmit the image information Ia to the detection unit410.

The detection unit 410 may receive the current input information Ib fromthe current input module 400. The detection unit 410 may detect thepredicted crack generation position on a crack occurrence portion of thechip 10 through the current input information Ib and the imageinformation Ia.

Referring again to FIG. 19, the TDR crack detection is performed (S100).

The TDR crack detection refers to the method described in FIG. 18. Sincethe crack detection method using the emission scope 1000 (S50) isdifferent from the TDR crack detection method, different results may beobtained. Therefore, the predicted crack generation position is detectedby first executing the crack detection method using the emission scope1000 (S50), and a very accurate crack position may be detected byexecuting the TDR crack detection (S100) on the basis of this detection.However, the inventive concept is not limited thereto.

Alternatively, the crack detection method according to the presentexemplary embodiment executes the TDR crack detection (S100) to detectthe predicted crack generation position, and may detect the accuratecrack position by executing the crack detection method using theemission scope 1000 (S50) on the basis of the predicted crack generationposition.

Hereinafter, a crack detection method according to an exemplaryembodiment of the inventive concept will be described with reference toFIGS. 12, 18, 21, and 22. Repeat descriptions will be omitted orsimplified.

FIG. 21 is a flowchart for explaining the crack detection methodaccording to an exemplary embodiment of the inventive concept, and FIG.22 is a flowchart for explaining an operation of determining thepresence or absence of a tPD crack of FIG. 21 in detail according to anexemplary embodiment of the inventive concept.

Referring to FIG. 21, the presence or absence of the tPD crack isdetermined (S40). Referring to FIG. 22, an input signal is applied(S41).

For example, referring to FIG. 12, the tPD unit 600 may apply the inputsignal to the first edge wiring 100. The input signal applied to thefirst edge wiring 100 by the tPD unit 600 travels along the first edgewiring 100 and may return to the tPD unit 600 again.

Referring again to FIG. 22, the arrival time of the input signal isdetected (S42).

For example, referring to FIG. 12, the tPD unit 600 may determine thepresence or absence of the crack by measuring the arrival time from thetime point at which the input signal is applied to the time point atwhich the input signal returns again. The tPD unit 600 may determine thepresence or absence of a crack by comparing the new arrival time withthe reference arrival time that is stored in advance in the case whereno crack exists. If the new arrival time is longer than the referencearrival time, the tPD unit 600 may determine that a crack exists.

Referring again to FIG. 21, the TDR crack detection is performed (S100).

The TDR crack detection refers to the method described in FIG. 18. Thecrack detection method according to the present exemplary embodimentfirst executes the tPD crack presence or absence determination (S40),and may execute the TDR crack detection (S100) only when it isdetermined that there is a crack. Accordingly, it is possible to enhancethe efficiency.

Hereinafter, a crack detection method according to an exemplaryembodiment of the inventive concept will be described with reference toFIGS. 13, 18, 21, and 23. Repeat descriptions will be omitted orsimplified.

FIG. 23 is a flowchart for explaining the crack detection methodaccording to an exemplary embodiment of the inventive concept.

Referring to FIG. 21, the tPD crack presence or absence determination isperformed (S40).

For example, referring to FIG. 23, first to n-th input signals areapplied (S43).

For convenience of explanation, n is set to 4. Referring to FIG. 13, thefirst tPD unit 600 a, the second tPD unit 600 b, the third tPD unit 600c, and the fourth tPD unit 600 d may apply the clock (CLK) signals toeach of the first divided edge wiring 150 a, the second divided edgewiring 150 b, the third divided edge wiring 150 c, and the fourthdivided edge wiring 150 d.

Referring again to FIG. 23, arrival times of the first to n-th inputsignals are detected (S44).

Referring to FIG. 13, the first tPD unit 600 a, the second tPD unit 600b, the third tPD unit 600 c, and the fourth tPD unit 600 d may detectthe respective arrival times.

Referring again to FIG. 23, a crack region is determined (S45).

Referring to FIG. 13, each tPD unit 600 may determine whether or not acrack exists by comparing a new arrival time with the reference arrivaltime. If the new arrival time is longer than the reference arrival time,it may be determined that a crack exists.

Referring again to FIG. 21, the TDR crack detection is performed (S100).

The above TDR crack detection refers to the method described in FIG. 18.The crack detection method according to the present exemplary embodimentfirst executes the tPD crack presence or absence determination (S40) andmay execute the TDR crack detection (S100) only when it is determinedthat there is a crack. Accordingly, it is possible to enhance theefficiency. Further, as it is possible to know which region of thedivided regions the crack is located through the tPD crack presence orabsence determination (S40), it is possible to have higher efficiency.

Hereinafter, a crack detection method according to an exemplaryembodiment of the inventive concept will be described with reference toFIGS. 18, 20, and 22 to 24. Repeat descriptions will be omitted orsimplified.

FIG. 24 is a flowchart for explaining the crack detection methodaccording to an exemplary embodiment of the inventive concept.

Referring to FIG. 24, the tPD crack presence or absence determination isperformed (S40).

The TDR crack presence or absence determination refers to the methoddescribed in FIG. 22 or 23.

Subsequently, the emission scope crack detection is performed (S50).

The emission scope crack detection refers to the method described inFIG. 20.

Subsequently, the TDR crack detection is performed (S100).

The TDR crack detection refers to the method described in FIG. 18.

In the crack detection method according to an exemplary embodiment ofthe inventive concept, the operations S50 and S100 may be executed in adifferent order.

While the inventive concept has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made thereto without departing from the spirit and scopeof the inventive concept as set forth by the following claims.

What is claimed is:
 1. A crack detection chip comprising: a chip whichincludes an internal region and an external region surrounding theinternal region; a guard ring formed inside the chip along an edge ofthe chip to define the internal region and the external region; an edgewiring disposed along an edge of the internal region in the form of aclosed curve; and a pad which is exposed on a surface of the chip and isconnected to the edge wiring, wherein the edge wiring is connected to aTime Domain Reflectometry (TDR) module configured to apply an incidentwave to the edge wiring through the pad, and detect a reflected waveformed in the edge wiring to detect a position of a crack.
 2. The crackdetection chip of claim 1, wherein the guard ring comprises first andsecond guard rings, and a distance between the first guard ring and theinternal region is larger than a distance between the second guard ringand the internal region.
 3. The crack detection chip of claim 1, whereina direction of an upper surface of the chip is a first direction, and awidth of the guard ring in the first direction is larger than a width ofthe edge wiring in the first direction.
 4. The crack detection chip ofclaim 1, wherein the edge wiring is connected to a current input moduleconfigured to apply a heat generation current to the edge wiring, andthe edge wiring is inspected by an emission scope configured to senseheat generated by the heat generation current.
 5. The crack detectionchip of claim 4, wherein the edge wiring comprises a first edge wiringand a second edge wiring which are separated from each other, the padcomprises first and second pads separated from each other and connectedto the first and second edge wirings, respectively, and the currentinput module applies heat generation currents of different magnitudes tothe first and second edge wirings through the first and second pads,respectively.
 6. The crack detection chip of claim 1, wherein the edgewiring is connected to a time propagation delay (tPD) unit configured toapply an input signal to the edge wiring through the pad, and determinethe presence or absence of a crack through a time at which the inputsignal propagates through the edge wiring.
 7. The crack detection chipof claim 6, further comprising: a divided edge wiring disposed along anedge of the internal region in the form of a closed curve and separatedfrom the edge wiring, wherein the divided edge wiring comprises first ton-th divided edge wirings divided from one another, the pad comprisesfirst to n-th pads connected to the first to n-th divided edge wirings,respectively, and the tPD unit comprises first through n-th input unitsconfigured to input first through n-th input signals to the firstthrough n-th divided edge lines, respectively, through the first throughn-th pads, respectively, to determine presence or absence of a crack. 8.The crack detection chip of claim 1, wherein the TDR module detects theposition of the crack through a time at which the reflected wave formedin the edge wiring is detected, and the reflected wave moves at leastonce along an entirety of the edge wiring and is detected by the TDRmodule.
 9. The crack detection chip of claim 1, wherein the edge wiringcomprises a first portion located at a first distance from the guardring, a second portion located at a second distance from the guard ring,and the second distance is greater than the first distance.
 10. Thecrack detection chip of claim 9, wherein the first and second portionsare alternately arranged on the closed curve of the edge wiring.
 11. Acrack detection chip comprising: a substrate including first and secondregions; a guard ring which separates the first and second regions; anedge wiring formed so as to be buried in the second region; and a padwhich is connected to the edge wiring and is exposed to an upper surfaceof the substrate, wherein the edge wiring is connected to a Time DomainReflectometry (TDR) module through the pad, and the TDR module isconfigured to apply an incident wave to the edge wiring, and detect areflected wave formed in the edge wiring to detect a position of acrack.
 12. The crack detection chip of claim 11, wherein the guard ringcomprises a metal.
 13. The crack detection chip of claim 11, wherein theedge wiring is connected to a current input module configured to apply aheat generation current to the edge wiring, and the edge wiring isinspected by an emission scope configured to sense heat generated by theheat generation current.
 14. The crack detection chip of claim 13,wherein the edge wiring is connected to a time propagation delay (tPD)unit configured to apply an input signal to the edge wiring through thepad, and determine the presence or absence of a crack through a time atwhich the input signal propagates through the edge wiring.
 15. The crackdetection chip of claim 11, wherein the edge wiring is connected to atime propagation delay (tPD) unit configured to apply an input signal tothe edge wiring through the pad, and determine the presence or absenceof a crack through a time at which the input signal propagates throughthe edge wiring.
 16. A crack detection chip comprising: an edge wiringarranged along an edge of a chip and formed in a closed curve shape; anda pad which is exposed to a surface of the chip and is connected to theedge wiring, wherein the edge wiring is connected to a Time DomainReflectometry (TDR) module configured to apply an incident wave to theedge wiring through the pad, and detect a reflected wave formed in theedge wiring to detect a position of a crack.
 17. The crack detectionchip of claim 16, wherein a horizontal shape of the chip is a rectanglehaving first to fourth sides, and the edge wiring comprises first tofourth lines corresponding to the first to fourth sides, respectively.18. The crack detection chip of claim 17, wherein the first to fourthlines extend substantially in parallel with the first to fourth sides,respectively.
 19. The crack detection chip of claim 16, wherein the edgewiring is buried in the chip.
 20. The crack detection chip of claim 16,further comprising: a contact which connects the edge wiring and thepad.